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<h2><span class="refentrytitle">Macro BOOST_TTI_HAS_STATIC_MEMBER_DATA</span></h2>
<p>BOOST_TTI_HAS_STATIC_MEMBER_DATA — A macro which expands to a metafunction which tests whether a static member data with a particular name and type exists. </p>
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<h2 xmlns:rev="http://www.cs.rpi.edu/~gregod/boost/tools/doc/revision" class="refsynopsisdiv-title">Synopsis</h2>
<div xmlns:rev="http://www.cs.rpi.edu/~gregod/boost/tools/doc/revision" class="refsynopsisdiv"><pre class="synopsis"><span class="comment">// In header: &lt;<a class="link" href="header/boost/tti/has_static_member_data_hpp.html" title="Header &lt;boost/tti/has_static_member_data.hpp&gt;">boost/tti/has_static_member_data.hpp</a>&gt;

</span>BOOST_TTI_HAS_STATIC_MEMBER_DATA(name)</pre></div>
<div class="refsect1">
<a name="idm10233"></a><h2>Description</h2>
<p>BOOST_TTI_HAS_STATIC_MEMBER_DATA is a macro which expands to a metafunction. The metafunction tests whether static member data with a particular name and type exists. The macro takes the form of BOOST_TTI_HAS_STATIC_MEMBER_DATA(name) where</p>
<p>name = the name of the inner member.</p>
<p>BOOST_TTI_HAS_STATIC_MEMBER_DATA generates a metafunction called "has_static_member_data_name" where 'name' is the macro parameter.</p>
<pre class="programlisting"><span class="keyword">template</span><span class="special">&lt;</span><span class="keyword">class</span> <span class="identifier">BOOST_TTI_TP_T</span><span class="special">,</span><span class="keyword">class</span> <span class="identifier">BOOST_TTI_TP_TYPE</span><span class="special">&gt;</span>
<span class="keyword">struct</span> <span class="identifier">has_static_member_data_</span><span class="char">'name'</span>
  <span class="special">{</span>
  <span class="keyword">static</span> <span class="keyword">const</span> <span class="identifier">value</span> <span class="special">=</span> <span class="identifier">unspecified</span><span class="special">;</span>
  <span class="keyword">typedef</span> <span class="identifier">mpl</span><span class="special">::</span><span class="identifier">bool_</span><span class="special">&lt;</span><span class="keyword">true</span><span class="special">-</span><span class="identifier">or</span><span class="special">-</span><span class="keyword">false</span><span class="special">&gt;</span> <span class="identifier">type</span><span class="special">;</span>
  <span class="special">}</span><span class="special">;</span>

<span class="identifier">The</span> <span class="identifier">metafunction</span> <span class="identifier">types</span> <span class="identifier">and</span> <span class="keyword">return</span><span class="special">:</span>

  <span class="identifier">BOOST_TTI_TP_T</span>    <span class="special">=</span> <span class="identifier">the</span> <span class="identifier">enclosing</span> <span class="identifier">type</span><span class="special">.</span>
                      <span class="identifier">The</span> <span class="identifier">enclosing</span> <span class="identifier">type</span> <span class="identifier">can</span> <span class="identifier">be</span> <span class="identifier">a</span> <span class="keyword">class</span><span class="special">,</span> <span class="keyword">struct</span><span class="special">,</span> <span class="identifier">or</span> <span class="keyword">union</span><span class="special">.</span>
                      <span class="identifier">If</span> <span class="identifier">the</span> <span class="identifier">type</span> <span class="identifier">is</span> <span class="identifier">a</span> <span class="keyword">union</span><span class="special">,</span> <span class="keyword">static</span> <span class="identifier">member</span> <span class="identifier">data</span> <span class="identifier">can</span> <span class="identifier">only</span>
                      <span class="identifier">be</span> <span class="identifier">found</span> <span class="keyword">if</span> <span class="identifier">the</span> <span class="identifier">C</span><span class="special">++</span><span class="number">11</span> <span class="identifier">unrestricted</span> <span class="keyword">union</span> <span class="identifier">is</span> <span class="identifier">implemented</span>
                      <span class="identifier">by</span> <span class="identifier">the</span> <span class="identifier">compiler</span> <span class="identifier">being</span> <span class="identifier">used</span><span class="special">,</span> <span class="identifier">since</span> <span class="identifier">prior</span> <span class="identifier">to</span> <span class="identifier">C</span><span class="special">++</span><span class="number">11</span> <span class="identifier">a</span> <span class="keyword">union</span>
                      <span class="identifier">could</span> <span class="identifier">not</span> <span class="identifier">have</span> <span class="keyword">static</span> <span class="identifier">data</span> <span class="identifier">members</span><span class="special">.</span>
  
  <span class="identifier">BOOST_TTI_TP_TYPE</span> <span class="special">=</span> <span class="identifier">the</span> <span class="identifier">type</span> <span class="identifier">of</span> <span class="identifier">the</span> <span class="keyword">static</span> <span class="identifier">member</span> <span class="identifier">data</span><span class="special">.</span>
         
  <span class="identifier">returns</span> <span class="special">=</span> <span class="char">'value'</span> <span class="identifier">is</span> <span class="keyword">true</span> <span class="keyword">if</span> <span class="identifier">the</span> <span class="char">'name'</span> <span class="identifier">exists</span><span class="special">,</span>
            <span class="identifier">with</span> <span class="identifier">the</span> <span class="identifier">appropriate</span> <span class="identifier">BOOST_TTI_TP_TYPE</span> <span class="identifier">type</span><span class="special">,</span>
            <span class="identifier">within</span> <span class="identifier">the</span> <span class="identifier">enclosing</span> <span class="identifier">BOOST_TTI_TP_T</span> <span class="identifier">type</span><span class="special">,</span>
            <span class="identifier">otherwise</span> <span class="char">'value'</span> <span class="identifier">is</span> <span class="keyword">false</span><span class="special">.</span>
</pre>
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